'Superman' Star Margot Kidder Dead at 69

Margot Kidder, the actress who played Lois Lane in “Superman,” died Sunday in Montana … TMZ has learned.

Margot was at her home when she passed away, according to the spokesperson at Franzen-Davis Funeral Home in Livingston, MT. The cause of death is unknown at this point.

Margot starred opposite Christopher Reeve in 1978’s “Superman,” and also in the 3 sequels. She continued acting right up until this year, taking small roles in TV shows and movies — but also had stage roles … including “The Vagina Monologues” on Broadway. She reportedly had 2 more roles yet to be released.

Margot had a very public battle with bipolar disorder for years. During her struggle she was briefly homeless in 1996. Margot became an advocate for mental health after that incident.

She’d been married 3 times, although she’d been single since the ’80s.